Pain management is an important aspect of post-operative recovery from surgery. Pain management usually begins immediately following the surgical procedure with the administration of narcotics or other pain control medications to the patient while the patient is under the direct supervision of the health care provider. The pain control medications are most commonly administered either orally or by injection.
The proliferation of less-invasive arthroscopic techniques for the surgical repair of many joint or soft tissue injuries and ailments has significantly reduced post-operative recovery times and the attendant pain experienced by the patient. The current trend toward arthroscopic techniques frequently enables surgical procedures to be performed on an outpatient basis or with shortened post-operative hospital stays. As a result, the bulk of the post-operative recovery time is spent in the home or even in the workplace. One goal of home recovery is to phase the patient back into routine physical activities relatively quickly as a means of shortening the post-operative recovery time.
Since the patient is generally not under the direct supervision of the health care provider when in the home or workplace, the responsibility for administering pain control medications falls on the patient in these environments. The vast majority of self-administered pain control medications are oral medications because most individuals lack the requisite knowledge, skill, and experience to self-administer pain control medications by injection. Unfortunately, however, pain control medications administered orally are transported throughout the body and correspondingly affect the entire body, often causing undesirable side effects such as drowsiness, disorientation, nausea, constipation or vomiting. In contrast, injected pain control medications can be administered more locally than orally administered medications, thereby frequently avoiding the undesirable side effects of oral medications. In addition, injected pain control medications reach the treatment site more rapidly and in greater concentrations than oral medications, rendering injected pain control medications a more effective pain control therapy.
To exploit the advantages of injected pain care medications, devices have been developed to inject the pain care medication into the treatment site in an automated manner, which requires minimal patient intervention. Such devices typically meter the pain care medication to the treatment site continuously over a long period of time. Automated continuous injection devices are, nevertheless, not entirely satisfactory. It has been found in many instances that pain care medication is most effective if periodically injected into the treatment site as a single relatively large bolus dosage whenever the patient senses the need rather than continuously injecting the same overall dosage of medication into the treatment site over a relatively long period of time. However, if the patient is allowed to self-administer injection of the pain care medication on an as needed basis in the absence of supervision of a health care provider, the risk of overmedication is significant.
The present invention recognizes a need for a fluid injection device, which selectively enables effective auto-administration of a fluid medication or, in the alternative, effective self-administration of the fluid medication by a patient while diminishing the risk of overmedication, even when the patient lacks the requisite knowledge, skill or experience to perform injections. Accordingly, it is an object of the present invention to provide a medication delivery system, wherein operation of the system is selective between an automated or extended mode and a manual or instantaneous mode. More particularly, it is an object of the present invention to provide such a medication delivery system, wherein the patient elects extended injection of a predetermined dosage of a fluid medication into a treatment site at a moderate flow rate over a long time or, in the alternative, elects to effect instantaneous injection of the predetermined dosage of the fluid medication into the treatment site at a higher flow rate over a short time. It is another object of the present invention to provide such a medication delivery system, wherein the system can effectively reduce the risk of overmedication even when the patient operates the system in the manual or instantaneous mode. It is still another object of the present invention to provide such a medication delivery system, wherein the system can be effectively monitored and operated by a patient lacking any specific medical knowledge, skill or experience in performing injections. It is yet another object of the present invention to provide such a medication delivery system, which is fully portable while operating so that the system can be used by the patient during normal daily activity.
These objects and others are accomplished in accordance with the invention described hereafter.